Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a first image in a sequence for a display screen or portion thereof with transitional graphical user interface showing our new design;

FIG. 2 is a second image thereof;

FIG. 3 is a third image thereof;

FIG. 4 is a fourth image thereof;

FIG. 5 is a fifth image thereof;

FIG. 6 is a sixth image thereof;

FIG. 7 is a seventh image thereof;

FIG. 8 is an eighth image thereof;

FIG. 9 is a ninth image thereof;

FIG. 10 is a tenth image thereof;

FIG. 11 is an eleventh image thereof;

FIG. 12 is a twelfth image thereof;

FIG. 13 is a thirteenth image thereof;

FIG. 14 is a fourteenth image thereof;

FIG. 15 is a fifteenth image thereof;

FIG. 16 is a sixteenth image thereof;

FIG. 17 is a seventeenth image thereof;

FIG. 18 is an eighteenth image thereof;

FIG. 19 is a nineteenth image thereof;

FIG. 20 is a twentieth image thereof; and,

FIG. 21 is a twenty-first image thereof.

The outer perimeter broken line depicting the display screen or portion thereof is for environmental purposes only and forms no part of the claimed design.

The remaining broken lines in the figures depict portions of the transitional graphical user interface that form no part of the claimed design.

The appearance of the graphical user interface sequentially transitions between the images shown in FIGS. 1-21. The process or period in which one image transitions to another forms no part of the claimed design. 

CLAIM We claim the ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 